Norovirus

What is Norovirus?

Norovirus (formerly known as Norwalk-like Virus) is one of the most common causes of vomiting and diarrhoea illness (gastro-enteritis) with 50,000 cases in New Zealand every year. Although Norovirus does not usually cause severe illness it can be particularly harmful to the elderly, infants and people with poor immune systems.

It is a major cause of non-bacterial food and waterborne outbreaks worldwide and tummy bug outbreaks in hospitals, early childhood centres, cruise ships and rest homes. Avoid visiting any facility experiencing a Norovirus outbreak. 

Many suspected food-borne illness incidents are actually caused by a Norovirus-infected person attending an event, rather than the food itself. 

What are the symptoms?

Symptoms may include:

• Vomiting
• Stomach cramps
• Diarrhoea
• Fever
• Headache
• Muscle/joints aches and pains
• Nausea
• Lack of energy 

Symptoms usually occur within 48 hours of exposure to an infected person, food or environment. A person is most infectious when they have diarrhoea and/or vomiting.  Most symptoms stop after two or three days.

How are people infected?

People are infected by swallowing and/or breathing in droplets containing the virus from the faeces or vomit of an infected person. Norovirus can spread a long way in a single episode of vomiting. Noroviruses can remain infectious on surfaces such as tables and curtains for several days.

Common ways of becoming infected include:

• Eating food or drinking water contaminated by faecal matter
• Person-to-person via tiny droplets hanging in the air from a person that has vomited
• By touching contaminated surfaces.

How is it treated?

No specific treatment is available but symptoms can be relieved by drinking plenty of fluids and taking paracetamol for the fever and pain. Using anti-diarrhoeal medications is not usually necessary because the illness doesn’t last long. If symptoms persist consult your GP. 

How do I protect myself and others?

• Avoid visiting any facility that is experiencing a Norovirus outbreak.
• Don't handle food if you have diarrhoea - you could spread the illness

Remember:

• Wash your hands:
  • After going to the toilet or changing nappies
  • After playing or working with animals
  • Before handling food
  • After being around people who are unwell

Airborne droplets of vomit can spread over a large area and settle on any surface so it’s important to clean at least a few metres around the obviously affected area.

• Surfaces should be washed with soap and water to remove soiling before disinfecting
• Use sodium hypochlorite (chlorine bleach) to clean your toilet and bathroom fixtures.

• Do not use bleach on surfaces that may leak colour, eg: carpet and furnishings.  Instead, use hot water and detergent and steam cleaners.
• Do not dry vacuum affected areas - use a wet vacuuming system.

Do I need to take time off work, school or preschool?

• Stay away from work, school or preschool when you have diarrhoea or vomiting and don't return until all symptoms have stopped for 48 hours. 
• Norovirus is a major issue in rest homes and hospitals. Stay away if you are unwell or if you are advised that there is an outbreak at the home or hospital.

For more information about this illness contact a Health Protection Officer on 0800 221 555.